1. Field of the Invention
In landscaping operations large grown trees are often transplanted to open areas to provide a pleasing appearance. The trees to be transplanted include a ball of earth about the essential root structure of the tree to be transplanted. The size of the ball depends on both the size of the tree and the size of the necessary root structure for survival of the type of tree. According to the size and type of tree the ball may be as large as four or five feet in diameter.
2. Related Art
In order to successfully plant such a tree a hole must be excavated to accommodate the ball of earth contained about the root structure. Excavations have been performed by hand using shovels or by use of a back hoe. While use of a back hoe may reduce the time necessary to make the hole, due to its digging action a much larger hole is often excavated than required for a ball. Additionally the shape of the hole is such that it may leave an unsightly scar in the landscaped area requiring some hand work to clean up the eyesore.
A need for a device that would quickly and neatly excavate a ball hole was thus seen. While combination auger and buckets are fairly old in the art none appear to be readily adapted for the purpose. For example Lyon in U.S. Pat. No. 173,482 discloses a boring cylinder divided into two parts with cutting edges only on the bottom. The rotational cutting force must be supplied through the walls of the cylinder. Additionally Lyon's auger cylinder requires a band to keep the two halves together during operation which might prove difficult to remove after the auger is lifted from the excavation. Hubbard in U.S. Pat. No. 185,638 discloses a similar earth auger having the similar characteristics to Lyon. Salyer in U.S. Pat. No. 154,962 discloses another version of an earth auger which includes cutting edges on the walls of the cylinder as well as bottom. Salyer's auger depends upon external tabs or lips bearing on the sides of the cylinder to prevent the halves from opening.
Richards in U.S. Pat. No. 146,475 discloses a clam-like auger for cleaning out wells which includes a sliding rotating member for opening a part of the shell to dump the excavation product. The cutting edge in Richard is also contained on the walls of the auger. Similar auger cylinders are disclosed by Needham in U.S. Pat. No. 244,819 and Gooder in U.S. Pat. No. 2,091,779. While each of the disclosed devices may perform their function well, due to the diameter of the excavation required for a tree root ball (often five feet or larger), the strength required in the cutting edge and their support is considerable. Such strength would require a heavy walled cylinder making the weight of the device practically unmanageable without expensive heavy equipment. Additionally the cylindrical shape of these devices would require a deeper excavation than necessary for a tree root ball.